功能导向过渡金属化合物析氢反应电催化剂的理论设计与性能研究

Fossil fuel is going to deplete. Moreover, the consumption of fossil fuel causes serious environmental problems. As a consequence, it is rather urgent to to develop new alternative clean and sustainable energy resource. Hydrogen is an efficient and green energy with great prospects. Compared with the other hydrogen production methods, electrocatalysis for splitting water to produce hydrogen has significant advantage, in which the performance of catalyst plays a key role. However, the low performance and high cost of existing catalysts limit their large-scale application, waiting for new catalysts with high performance and low cost. Previously, theoretical design of catalysts was usually based on single performance target. However, synergistic effect of multi-performance is of great significance for high performance catalysts. In this project, functional orientation is performed with multiple objectives (free energy, energy barrier of reaction, conductivity, and stability) in combination with swarm intelligence structure prediction method and first-principle calculations. In view of the catalytic activity of materials in various stoichiometries and in different dimensions, we focus on transition metal phosphides, carbides, nitrides, and sulfides to design electrocatalytic materials with low cost and excellent performance from multiple dimensions (three-dimensional crystals, two-dimensional materials, zero-dimensional clusters), accelerating the development process of hydrogen energy. In addition, combining with the latest experimental research progress, we determine the surface structure and composition, active site, catalytic mechanism, and interaction between catalyst and electrode of new catalyst, providing theoretical basis for the performance improvement.

化石能源日趋枯竭以及化石能源消耗引发的环境问题日趋严重，开发清洁、可持续发展新能源迫在眉睫。氢气是有巨大发展前景的高效绿色能源。相比于其它制氢方法，电催化分解水具有显著优势，其中催化剂性能是高效电催化分解水制氢的关键。然而，现存催化剂的性能和成本限制其大规模应用，亟待开发设计高性能催化剂。此前催化剂的理论设计以单一性能为目标，高性能催化剂需要多性能协调统一。本项目以多目标为功能导向（反应自由能、反应能垒、导电性和稳定性），结合群智能结构预测方法与第一性原理计算，以过渡金属磷、碳、氮、硫化物为研究对象，兼顾变化学组分和材料在不同维度下的催化活性，多维度（三维晶体、二维晶体、零维团簇）地设计性能优越的电催化剂，加快氢能源的研发进程。同时，结合实验最新研究进展，确定新型催化剂的表面结构及组分、活性位点、催化机理和催化剂与电极之间的相互作用，为性能改进提供理论依据。

高效电催化分解水急需设计与研发性能优异的催化剂。本项目在国家自然科学基金支持下，利用第一性原理计算方法，提出18个高稳定性和高导电性的候选结构，优选出6个性能优异的析氢反应催化剂（FeP3、FeC6N、Mo2P3、La3C2、MoCP和MoCN），取得了一系列创新性成果。研究结果表明，优化结构中金属含量能够有效调控非金属原子的电荷数，实现了非金属原子对氢的有效吸附，提升了活性位点密度；利用量子限域效应，稳定了含新奇配位数的结构，有效地提升析氢反应活性；发现了催化剂的活性位点密度与金属原子在费米能级处轨道占有率呈负相关的规律；探索了缺陷和应变对催化活性的调控。我们的工作为实验合成高性能电催化剂提供了重要科学参考。